U.S. patent application number 15/700602 was filed with the patent office on 2018-03-22 for gear apparatus.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. The applicant listed for this patent is TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Yota MIZUNO, Masataka SUGIYAMA.
Application Number | 20180080542 15/700602 |
Document ID | / |
Family ID | 61618448 |
Filed Date | 2018-03-22 |
United States Patent
Application |
20180080542 |
Kind Code |
A1 |
SUGIYAMA; Masataka ; et
al. |
March 22, 2018 |
Gear Apparatus
Abstract
A gear apparatus according to the present disclosure includes: a
sun gear; a carrier to which planetary gear shafts rotatably
supporting multiple planetary gears meshing with this sun gear are
fixed; an external gear portion; a gear cylinder having an internal
gear portion meshing with the planetary gears; a gear meshing with
the external gear portion of the gear cylinder; a lubricating oil
passage formed in the planetary gears shafts, the lubricating oil
passage configured to supply the lubricating oil to respective
mashing parts between the planetary gears and the internal gear
portion and between the planetary gears and the sun gear; and a
lubricating oil guiding passage having one end opening to an inner
circumferential surface of the gear cylinder, and discharging the
lubricating oil present on an inner circumferential surface of the
gear cylinder toward the meshing part between the external gear
portion and the gear.
Inventors: |
SUGIYAMA; Masataka;
(Toyota-shi, JP) ; MIZUNO; Yota; (Nisshin-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOYOTA JIDOSHA KABUSHIKI KAISHA |
Toyota-shi |
|
JP |
|
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
61618448 |
Appl. No.: |
15/700602 |
Filed: |
September 11, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H 57/0426 20130101;
B60K 6/365 20130101; B60K 6/40 20130101; B60Y 2200/92 20130101;
Y10S 903/91 20130101; F16H 57/043 20130101; F16H 57/08 20130101;
F16H 57/0482 20130101; F16H 3/724 20130101; F16H 1/28 20130101;
F16H 57/082 20130101; B60K 6/405 20130101; B60K 6/445 20130101;
F16H 57/0471 20130101 |
International
Class: |
F16H 57/04 20060101
F16H057/04; F16H 1/28 20060101 F16H001/28; F16H 57/08 20060101
F16H057/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 20, 2016 |
JP |
2016-183407 |
Claims
1. A gear apparatus comprising: a sun gear; a plurality of
planetary gears that mesh with the sun gear; a plurality of
planetary gear shafts that rotatably support the plurality of
planetary gears respectively; a carrier disposed concentrically to
the sun gear, the carrier connected to the plurality of planetary
gear shafts; a gear cylinder disposed concentrically to the sun
gear such that the gear cylinder surrounds the plurality of
planetary gears, the gear cylinder including an external gear
portion, and an internal gear portion that meshes with the
plurality of planetary gears; and a first gear that meshes with the
external gear portion, at least one of the plurality of planetary
gear shafts including a lubricating oil passage configured to
supply a lubricating oil to a meshing part between the plurality of
planetary gears and the internal gear portion, and to a meshing
part between the plurality of planetary gears and the sun gear, and
the gear cylinder including a lubricating oil guiding passage that
has an opening communicated to an inner circumferential surface of
the gear cylinder at one end of the lubricating oil guiding
passage, the lubricating oil guiding passage configured to
discharge the lubricating oil present on the inner circumferential
surface of the gear cylinder toward a meshing part between the
external gear portion and the first gear.
2. The gear apparatus according to claim 1, wherein the lubricating
oil guiding passage includes: a communicating hole opening to an
inner circumferential surface and an outer circumferential surface
of the gear cylinder; and a tubular nozzle member configured such
that a base end of the tubular nozzle member is coupled to an
opening portion of the communicating hole on an outer
circumferential surface of the gear cylinder, and a front end of
the tubular nozzle member opens toward the meshing part between the
external gear portion of the gear cylinder and the gear.
3. The gear apparatus according to claim 1, further comprising a
pair of bearings disposed to both ends of the inner circumferential
surface of the gear cylinder in a longitudinal direction of the
gear cylinder such that the pair of bearings rotatably support the
gear cylinder, wherein the pair of bearings is configured such that
an inner diameter of the inner circumferential surface of the gear
cylinder between one of the pair of bearings and the internal gear
portion is greater than an inner diameter of the inner
circumferential surface of the gear cylinder between the other one
of the pair of bearings and the internal gear portion, and the one
end of the lubricating oil guiding passage opens to the inner
circumferential surface of the gear cylinder, the inner
circumferential surface being located between the one of the pair
of bearings and the internal gear portion.
4. The gear apparatus according to claim 1, wherein the gear
apparatus is configured such that the lubricating oil is supplied
to the lubricating oil passage by an oil pump.
Description
INCORPORATION BY REFERENCE
[0001] The disclosure of Japanese Patent Application No.
2016-183407 filed on Sep. 20, 2016 including the specification,
drawings and abstract is incorporated herein by reference in its
entirety.
BACKGROUND
1. Technical Field
[0002] The present disclosure relates to a gear apparatus including
a gear cylinder formed with an external gear portion and an
internal gear portion, planetary gears meshing with the internal
gear portion of this gear cylinder, and a gear meshing with the
external gear portion of the gear cylinder.
2. Description of Related Art
[0003] In a vehicle including a transaxle-type power transmission
mechanism in which a transmission and a differential unit, such as
a speed change gear and a power distribution apparatus, are
integrated, a scoop-up lubrication using a final reduction gear of
a differential unit is common as a lubrication method for the power
transmission mechanism. In this scoop-up lubrication, the
differential unit is disposed to a lower end part of a transaxle
case, and a lower end portion of the final reduction gear is set in
a state of being soaked in a lubricating oil flowing into the lower
end part of the transaxle case. Through this configuration, the
lubricating oil is scooped up along with rotation of the final
reduction gear so as to transfer the lubricating oil to respective
meshing parts among gear elements composing the transmission.
[0004] Meanwhile, in a hybrid vehicle using both an engine and a
rotary machine as motors, there has been known one using a
planetary gear mechanism as a power distribution apparatus to split
a motive power from the engine and a motive power from the rotary
machine. In a vehicle including such a planetary gear mechanism,
since a distance from the final reduction gear of the differential
unit to the planetary gear mechanism is relatively far, a scoop-up
lubrication does not work so effectively, so that a forced
lubrication using an oil pump is employed, instead.
[0005] Japanese Patent Application Publication No. 2016-098909
discloses such a lubrication system, and a lubricating oil is
supplied from a carrier side of a planetary gear mechanism to
respective meshing parts between the planetary gear and a sun gear
and between the planetary gear and an internal gear portion. In
this JP 2016-098909 A, the final reduction gear of the differential
unit meshes with a small gear of a secondary shaft. In addition, a
large gear that is adjacent to this small gear and provided to the
secondary shaft meshes with an external gear portion formed on an
outer circumferential surface of a gear cylinder having an internal
gear portion of the planetary gear mechanism formed on its inner
circumferential surface, and also meshes with a gear integrally
rotating with a rotor shaft of the rotary machine at the same
time.
SUMMARY
[0006] In a hybrid vehicle disclosed in Japanese Patent Application
Publication No. 2016-098909, the lubricating oil supplied from the
carrier side of the planetary gear mechanism to the respective
meshing parts of the planetary gears with the sun gear and with the
internal gear is guided to the inner circumferential surface of the
gear cylinder by centrifugal force along with rotation of the gear
cylinder. The lubricating oil is supplied from an oil discharge
passage that opens to the inner circumferential surface and the
outer circumferential surface of this gear cylinder to the small
gear of the secondary shaft. In the meantime, a lubricating oil
scooped up by the final reduction gear of the differential unit is
supplied to the meshing part of this final reduction gear with the
small gear. Hence, it is possible to sufficiently supply the
lubricating oil to the small gear of the secondary shaft.
[0007] Unfortunately, it cannot be said that the lubricating oil is
sufficiently supplied to the meshing part between the external gear
portion of the gear cylinder of the planetary gear mechanism having
a farther distance from the final reduction gear of the
differential unit and the large gear that is adjacent to the small
gear of the secondary shaft, and meshes with the external gear
portion of the gear cylinder.
[0008] It can be considered that amount of the lubricating oil
flowing into the lower end part of the transaxle case is increased
so as to increase the supply amount of the lubricating oil to the
aforementioned meshing part between the external gear portion of
the gear cylinder of the planetary gear mechanism and the large
gear of the secondary shaft. However, this method causes increase
in energy loss to the final reduction gear of the differential unit
due to increase in resistance to stirring resulting from the
increase in amount of the lubricating oil.
[0009] The present disclosure provides a gear apparatus that can
efficiently lubricate a meshing part between an external gear
portion of a gear cylinder and a gear meshing with this external
gear portion without increasing amount of the lubricating oil to be
reserved in a transaxle.
[0010] A gear apparatus according to the present disclosure
includes: a sun gear; a carrier disposed concentrically to the sun
gear, the carrier to which multiple planetary gear shafts rotatably
supporting respective multiple planetary gears meshing with the sun
gear are fixed; a gear cylinder disposed concentrically to the sun
gear in a manner as to surround the multiple planetary gears, the
gear cylinder including an external gear portion, and an internal
gear portion meshing with the multiple planetary gears; a gear
meshing with the external gear portion; a lubricating oil passage
formed in the planetary gear shafts, the lubricating oil passage
configured to supply a lubricating oil to respective meshing parts
between the planetary gears and the internal gear portion of the
gear cylinder and between the planetary gears and the sun gear; and
a lubricating oil guiding passage whose one end opens to an inner
circumferential surface of the gear cylinder, the lubricating oil
guiding passage guiding the lubricating oil present on the inner
circumferential surface of the gear cylinder toward the meshing
part between the external gear portion of the gear cylinder and the
gear.
[0011] In the present disclosure, the lubricating oil flows through
the lubricating oil passage formed in the planetary gears, and is
supplied to the meshing parts between the planetary gears and the
internal gear portion of the gear cylinder and between the
planetary gears and the sun gear. The lubricating oil is then
guided to the inner circumferential surface of the gear cylinder by
centrifugal force, flows through the lubricating oil guiding
passage whose one end opens to this inner circumferential surface,
and is then supplied to the meshing part between the external gear
portion of the gear cylinder and the gear.
[0012] In the gear apparatus of the present disclosure, the
lubricating oil guiding passage can be defined by a communicating
hole opening to the inner circumferential surface and an outer
circumferential surface of the gear cylinder; and a tubular nozzle
member whose base end is coupled to an opening portion of the
communicating hole on the outer circumferential surface side of the
gear cylinder, and whose front end opens toward the meshing part
between the external gear portion of the gear cylinder and the
gear.
[0013] There is further provided a pair of bearings disposed to
both longitudinal ends of the inner circumferential surface of the
gear cylinder so as to rotatably support the gear cylinder, and it
is effective that an inner diameter of the inner circumferential
surface of the gear cylinder between one bearing of the pair of
bearings and the internal gear portion is set to be greater than an
inner diameter of the inner circumferential surface of the gear
cylinder between the other bearing of the pair of bearings and the
internal gear portion, and one end of the lubricating oil guiding
passage is set to open to the inner circumferential surface of the
gear cylinder, the inner circumferential surface being located
between the one of the bearings and the internal gear portion.
[0014] The lubricating oil can be supplied to the lubricating oil
passage by using an oil pump.
[0015] According to the gear apparatus of the present disclosure,
since the gear apparatus includes the lubricating oil guiding
passage whose one end opens to the inner circumferential surface of
the gear cylinder, the lubricating oil guiding passage discharging
the lubricating oil present on the inner circumferential surface of
the gear cylinder to the meshing part between the external gear
portion of the gear cylinder and the gear, it is possible to guide
the lubricating oil present on the inner circumferential surface of
the gear cylinder to the meshing part between the external gear
portion and the gear. As a result, it is possible to efficiently
supply the lubricating oil to the meshing part between the external
gear portion of the gear cylinder and the gear meshing with this
external gear portion.
[0016] In the case of defining the lubricating oil guiding passage
by coupling the base end of the tubular nozzle member to the
opening portion of the outer circumferential surface of the gear
cylinder, it is possible to discharge the lubricating oil to the
meshing part between the external gear portion and the gear without
forming the communicating hole to open to the external gear portion
of the gear cylinder. As a result, it is possible to efficiently
supply the lubricating oil to the meshing part between the external
gear portion and the gear without causing deterioration of strength
of the external gear portion.
[0017] In the case of setting the inner diameter of the inner
circumferential surface of the gear cylinder between one of the
bearings and the internal bearing portion to be greater than the
inner diameter of the inner circumferential surface of the gear
cylinder between the other of the bearings and the internal gear
portion, and forming the one end of the lubricating oil guiding
passage to open to this, it is possible to efficiently guide the
lubricating oil flowing to the inner circumferential surface of the
gear cylinder to the lubricating oil guiding passage.
[0018] In the case of supplying the lubricating oil to the
lubricating oil passage by an oil pump, it is possible to surely
supply the lubricating oil to the meshing part between the sun gear
and the internal gear portion of the gear cylinder.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Features, advantages, and technical and industrial
significance of exemplary embodiments of the disclosure will be
described below with reference to the accompanying drawings, in
which like numerals denote like elements, and wherein:
[0020] FIG. 1 is a schematic view showing a configuration outline
of one embodiment in which a gear apparatus according to the
present disclosure is installed in a hybrid vehicle;
[0021] FIG. 2 is a side view of a part of a transaxle case in the
hybrid vehicle shown in FIG. 1; and
[0022] FIG. 3 is an extracted enlarged sectional view of a part of
a planetary mechanism in FIG. 1.
DETAILED DESCRIPTION OF EMBODIMENTS
[0023] One embodiment of a gear apparatus according to the present
disclosure applied to a hybrid vehicle will be described in detail
with reference to FIG. 1 to FIG. 3. However, the present disclosure
is not limited to such an embodiment, but is applicable to any gear
apparatus belonging to the spirit of the present disclosure.
[0024] FIG. 1 shows a configuration outline of a hybrid vehicle in
the present embodiment is schematically shown in FIG. 1, and FIG. 2
shows schematically a side shape of a housing part of the transaxle
case.
[0025] The hybrid vehicle in the present embodiment includes one
internal combustion engine, that is, an engine 10, a first electric
rotary machine 20, and a second electric rotary machine 30, as
motors; but the present disclosure is not limited to this. The
present disclosure is applicable to a hybrid vehicle composed of
one engine and one rotary machine as motors.
[0026] In the hybrid vehicle in the present embodiment, an EV mode
in which only the electric rotary machines 20, 30 are operated with
the engine 10 stopped and an HV mode in which the electric rotary
machines 20, 30 and the engine 10 are both operated are switched
from one to the other depending on the driving condition of the
vehicle.
[0027] A power transmission system T including a planetary gear
train 40 and a differential unit 50 is installed between the engine
10 and driven wheels W and between the two electric rotary machines
20, 30 and the driven wheels W. Axles W.sub.A of the pair of right
and left driven wheels W are coupled to a pair of right and left
differential shafts 51 of the differential unit 50 protruding to
the right side and the left side from side ends of a housing
C.sub.A and a casing C.sub.B of a transaxle case C.
[0028] FIG. 3 shows an extracted and enlarged part of the planetary
gear train 40 in FIG. 1 installed between the engine 10 and the
first electric rotary machine 20. One end portion (the right side
in FIG. 2) of an engine output shaft 11 is coupled via a not-shown
torsional vibration damper to the engine 10. One end portion (the
right side in FIG. 2) of a pump driving shaft 12 is spline-fitted
to the other end portion of this engine output shaft 11, and a
mechanical oil pump 60 is coupled to the other end portion of the
pump driving shaft 12. This mechanical oil pump 60 is used for
supplying a lubricating oil O to the power transmission system T
and others, and is operated along with the engine 10.
[0029] The pump driving shaft 12 is formed with a lubricating oil
supply passage 12a extending through the pump driving shaft 12 in a
longitudinal direction thereof, and one end of this lubricating oil
supply passage 12a communicates with a central oil passage 11a so
formed as to extend from the other end of an engine output shaft 11
throughout a longitudinal central potion thereof. The lubricating
oil O discharged from the mechanical oil pump 60 and a not-shown
electric oil pump is supplied into the lubricating oil supply
passage 12a.
[0030] A rotor 22 of the first electric rotary machine 20 is
attached to a hollow rotor shaft 21 surrounding the pump driving
shaft 12. A stator 23 of the first electric rotary machine 20,
which surrounds this rotor 22, is fixed along with a stator 31 of
the second electric rotary machine 30 to the casing C.sub.B of the
transaxle case C. Both ends of the rotor shaft 21 of the first
electric rotary machine 20 are rotatably supported relative to the
casing C.sub.B, and the other end of the aforementioned pump
driving shaft 12 is also rotatably supported relative to the casing
C.sub.B. One end of the engine output shaft 11 is rotatably
supported relative to the housing C.sub.A of the transaxle case C.
A needle roller bearing 13 is installed between the other end of
the engine output shaft 11 disposed into an inner side of one end
(the right side in FIG. 2) of the rotor shaft 21 of the first
electric rotary machine 20 and the rotor shaft 21 of the first
electric rotary machine 20. Through this, the engine output shaft
11 is set in a state of being relatively rotatable with respect to
the rotor shaft 21 of the first electric rotary machine 20.
[0031] One end (the right side in FIG. 3) of a hollow sun gear 41
disposed concentrically to the engine output shaft 11 in a manner
as to surround the engine output shaft 11 is formed with a sun gear
portion 41a, and the other end of this sun gear 41 is spline-fitted
to one end of the rotor shaft 21 of the first electric rotary
machine 20. Multiple planetary gear shafts 43 are fixed to a
disk-shaped carrier 42 that is fixed to the engine output shaft 11
in a manner as to surround the sun gear portion 41a in parallel to
a rotational axial line of the engine output shaft 11, and project
from the carrier 42. Planetary gears 44 meshing with the sun gear
portion 41a are rotatably supported to the respective planetary
gear shafts 43 via needle roller bearings 45. An inner
circumferential surface of the gear cylinder 46 disposed
concentrically to the sun gear 41 in a manner as to surround these
planetary gears 44 is formed with an internal gear portion 46a
meshing with the planetary gears 44. Both longitudinal ends of the
gear cylinder 46 is rotatably supported to the casing C.sub.B and
the housing C.sub.A of the transaxle case C via a pair of ball
bearings 47a, 47b, and an outer circumferential surface of the gear
cylinder 46 is formed with an external gear portion 46b meshing
with a large gear 71 of a secondary shaft 70.
[0032] The differential unit 50 is disposed to a lower end part of
the transaxle case C in which the lubricating oil O is sealed, and
the lubricating oil O flows down into an oil reservoir C.sub.1 in
the lower end part of the transaxle case C by gravity. When a
vehicle is in a driving state, as indicated by a two-dot chain line
in FIG. 2, amount of the lubricating oil O reserved in the
transaxle case C may be set such that an entire part of the gear
located at the lower most end of the final reduction gear 52 of the
differential unit 50 is soaked in the lubricating oil O. Both ends
of the secondary shaft 70 disposed above the differential unit 50
is rotatably supported by the housing C.sub.A and the casing
C.sub.B of the transaxle case C. A large gear 71, which meshes with
the external gear portion 46b of the gear cylinder 46 of the
planetary gear train 40 and a small gear 33a of the motor output
shaft 33 spline-fitted to a rotor shaft 32 of the second electric
rotary machine 30 is fixed to one end (the right side in FIG. 2) of
the secondary shaft 70. On the lateral side of the large gear 71 at
the other end of the secondary shaft 70, there is formed an output
gear 70a meshing with the final reduction gear 52 of the
differential unit 50.
[0033] Further, the motor output shaft 33 is disposed above the
secondary shaft 70, and is located substantially right above the
differential unit 50. Relative to the differential unit 50, the
aforementioned engine output shaft 11 is located more frontward
than the secondary shaft 70, and is located further apart from the
differential unit 50 than the secondary shaft 70 is. A distance
from a rotary axial line of the final reduction gear 52 of the
differential unit 50 to a rotary axial line of the external gear
portion 46b of the gear cylinder 46 of the planetary gear train 40
is longer than a distance from a rotary axial line of the final
reduction gear 52 of the differential unit 50 to a rotary axial
line of the large gear 71 of the secondary shaft 70.
[0034] Meanwhile, the lubricating oil O in the oil reservoir
C.sub.1 is scooped up along with rotation of the final reduction
gear 52 of the differential unit 50, and thus it is possible to
supply the lubricating oil O to the output gear 70a of the
secondary shaft 70 meshing with this final reduction gear 52.
[0035] However, it cannot be said that a sufficient amount of the
lubricating oil O is supplied to the meshing part of the external
gear portion 46b of the gear cylinder 46 having a farther distance
from the final reduction gear 52 of the differential unit 50 with
the large gear 71 of the secondary shaft 70. To cope with this, in
the present embodiment, there is provided a tubular nozzle member
48, as will be described latter.
[0036] Each of the planetary gear shafts 43 is formed with a
central oil passage 43a extending along a longitudinal direction
thereof, and a radial oil passage 43b whose radially inner side
communicates with this central oil passage 43a, and whose radially
outer side opens to the outer circumferential surface of the
planetary gear shaft 43 so as to supply the lubricating oil to the
needle roller bearing 45. The carrier 42 is formed with a
connecting oil passage 42a whose radially inner side communicates
with an oil passage extending from the central oil passage 11a of
the engine output shaft 11 in the radial direction, and whose
radially outer side communicates with the central oil passages 43a
of the planetary gear shafts 43. The central oil passage 43a and
the radial oil passage 43b function as a lubricating oil passage of
the present disclosure.
[0037] A portion of the gear cylinder 46, which is located between
the internal gear portion 46a of the gear cylinder 46 of the
planetary gear train 40 and the ball bearing 47a on one side, and
is apart from a lateral end of the internal gear portion 46a of the
gear cylinder 46, is formed with more than one communicating hole
46c opening to the inner circumferential surface and the outer
circumferential surface of this gear cylinder 46. A tubular nozzle
member 48 that guides the lubricating oil O flowing through the
communicating hole 46c to the meshing part between the external
gear portion 46b of the gear cylinder 46 and the large gear 71 of
the secondary shaft 70 is coupled to the opening portion of the
communicating hole 46c located on the outer circumferential surface
side. A base end of the tubular nozzle member 48 is coupled to the
opening portion on the outer circumferential surface side of the
communicating hole 46c, and a front end portion thereof is bent
toward the external gear portion 46b of the gear cylinder 46, and a
front end thereof opens toward the meshing part between the
external gear portion 46b and the large gear 71. Through this, the
lubricating oil O present on the inner circumferential surface of
the gear cylinder 46 is brought to be discharged toward the meshing
part between the external gear portion 46b and the large gear
71.
[0038] Hence, the lubricating oil O flowing through the lubricating
oil supply passage 12a of the pump driving shaft 12 flows from the
central oil passage 11a of the engine output shaft 11 through the
connecting oil passage 42a of the carrier 42, and is guided to the
central oil passages 43a of the planetary gear shafts 43. The
lubricating oil O is then supplied to the meshing parts of the
needle roller bearings 45 disposed between the planetary gear
shafts 43 and the planetary gears 44 and the planetary gears 44
with the internal gear portion 46a of the gear cylinder 46 and the
sun gear 41. The lubricating oil O further flows along the inner
circumferential surface of the gear cylinder 46 by centrifugal
force, and lubricates the ball bearings 47a, 47b disposed between
both ends of the gear cylinder 46, and the casing C.sub.B and the
housing C.sub.A. At the same time, part of the lubricating oil O
present on the inner circumferential surface of the gear cylinder
46 is supplied from the communicating hole 46c via the tubular
nozzle member 48 to the meshing part between the external gear
portion 46b and the large gear 71; and as a result, the lubricating
oil O is also supplied to the small gear 33a of the motor output
shaft 33 meshing with the large gear 71.
[0039] In this manner, the lubricating oil O guided from the
communicating hole 46c to the external gear portion 46b of the gear
cylinder 46 by the tubular nozzle member 48 is guided to the large
gear 71 of the secondary shaft 70 and the small gear 33a of the
motor output shaft 33. Eventually, the lubricating oil O flows down
into the oil reservoir C.sub.1 at the lower end part of the
transaxle case C by gravity.
[0040] In the present embodiment, the lubricating oil guiding
passage of the present disclosure is defined by the communicating
hole 46c and the tubular nozzle member 48, but the communicating
hole 46c may be configured to open to the external gear portion 46b
of the gear cylinder 46, to thereby eliminate the tubular nozzle
member 48. In this case, the lubricating oil guiding passage of the
present disclosure may be defined by only the communicating hole
46c.
[0041] However, if an opening portion is formed to the external
gear portion 46b of the gear cylinder 46 to which a great
transmission torque is applied, deterioration of strength of the
external gear portion 46b might be caused. In this respect, in the
present embodiment, without configuring the communicating hole 46c
to open to the external gear portion 46b of the gear cylinder 46,
the lubricating oil O can be guided to the meshing part between the
external gear portion 46b and the large gear 71, thus causing no
deterioration of strength of the external gear portion 46b.
[0042] In such a manner that the lubricating oil O is discharged
from the communicating hole 46c toward the meshing part between the
external gear portion 46b of the gear cylinder 46 and the large
gear 71, the communicating hole 46c may be inclined relative to the
radial direction of the gear cylinder 46, to thereby eliminate the
tubular nozzle member 48. In this case, the lubricating oil guiding
passage of the present disclosure can be defined by only the
communicating hole 46c.
[0043] In this manner, the lubricating oil O supplied to the
planetary gear train 40 through a forced lubrication by the
mechanical oil pump 60 and the electric oil pump can be guided to
the meshing part between the external gear portion 46b of the gear
cylinder 46 and the large gear 71 of the secondary shaft 70 via the
communicating hole 46c and the tubular nozzle member 48. Through
this configuration, it is possible to securely supply the
lubricating oil O to the meshing part between the external gear
portion 46b of the gear cylinder 46 and the large gear 71 of the
secondary shaft 70. In addition, the amount of the lubricating oil
reserved in the oil reservoir C.sub.1 of the housing C.sub.A is
minimized so as to prevent increase in resistance to stirring of
the lubricating oil O relative to the final reduction gear 52 of
the differential unit 50.
[0044] In the present embodiment, the inner diameter d1 of the part
of the gear cylinder 46, the part being located between the
external gear portion 46b and the ball bearing 47a on one side is
set to be greater than the inner diameter d.sub.2 of the part of
the gear cylinder 46, the part being located between the internal
gear portion 46a and the ball bearing 47b on the other side. In
this configuration, it is considered to guide a greater amount of
the lubricating oil O from here to the communicating hole 46c.
[0045] It should be noted that the present disclosure should be
interpreted based only upon matters described in the scope of
claims, and in the aforementioned embodiments, all changes and
modifications contained within the concept of the present
disclosure can be made in addition to the matters described
therein. That is, all the matters in the aforementioned embodiments
are not elements for limiting the present disclosure and can change
arbitrarily corresponding to the application and purpose, including
constructions having no direct relation to the present
disclosure.
[0046] The present disclosure may also be defined as follows. A
gear apparatus includes: a sun gear; a plurality of planetary gears
that mesh with the sun gear; a plurality of planetary gear shafts
that rotatably support the plurality of planetary gears
respectively; a carrier disposed concentrically to the sun gear,
the carrier connected to the plurality of planetary gear shafts; a
gear cylinder disposed concentrically to the sun gear such that the
gear cylinder surrounds the plurality of planetary gears, the gear
cylinder including an external gear portion, and an internal gear
portion that meshes with the plurality of planetary gears; and a
gear that meshes with the external gear portion, at least one of
the plurality of planetary gear shafts including a lubricating oil
passage configured to supply a lubricating oil to a meshing part
between the plurality of planetary gears and the internal gear
portion, and to a meshing part between the plurality of planetary
gears and the sun gear, and the gear cylinder including a
lubricating oil guiding passage that has an opening communicated to
an inner circumferential surface of the gear cylinder at one end of
the lubricating oil guiding passage, the lubricating oil guiding
passage configured to discharge the lubricating oil present on the
inner circumferential surface of the gear cylinder toward the
meshing part between the external gear portion and the gear. The
lubricating oil guiding passage may include: a communicating hole
opening to an inner circumferential surface and an outer
circumferential surface of the gear cylinder; and a tubular nozzle
member configured such that a base end of the tubular nozzle member
is coupled to an opening portion of the communicating hole on an
outer circumferential surface of the gear cylinder, and a front end
of the tubular nozzle member opens toward the meshing part between
the external gear portion of the gear cylinder and the gear. The
gear apparatus may further includes a pair of bearings disposed to
both ends of the inner circumferential surface of the gear cylinder
in a longitudinal direction of the gear cylinder such that the pair
of bearings rotatably support the gear cylinder. The pair of
bearings may be configured such that an inner diameter of the inner
circumferential surface of the gear cylinder between one of the
pair of bearings and the internal gear portion is greater than an
inner diameter of the inner circumferential surface of the gear
cylinder between the other one of the pair of bearings and the
internal gear portion, and the one end of the lubricating oil
guiding passage may open to the inner circumferential surface of
the gear cylinder, the inner circumferential surface being located
between the one of the pair of bearings and the internal gear
portion. The gear apparatus may be configured such that the
lubricating oil is supplied to the lubricating oil passage by an
oil pump.
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